The invention concerns a unit consisting of a bearing equipped with a data sensor device and a housing inside which the bearing is coupled.
Such units permit, on the one hand, a turning body to rotate by attaching it to a turning collar and, on the other hand, the bearing and the body to be locked in position in relation to the housing.
The invention likewise concerns a steering system for an automobile consisting of a steering column coupled to the inner collar of such a unit and a steering tube in which the housing is formed to receive said column in rotation.
In such units, when the bearing is equipped with a device to detect rotating speed, angular position, and/or the rotating direction of the turning collar in relation to the fixed collar, the data may be converted into signals as a function of the torque exerted on the column by means of the steering wheel, which signals are used by a power steering computer.
In another example of an application, such units are used for automobile vehicle wheels that are equipped with anti-lock systems; the data are then used, in particular, by a power brake computer.
Bearings equipped with a data sensor device consisting of a coder that generates magnetic impulses attached to the turning collar and a sensor equipped with at least two sensitive components capable of detecting such impulses attached to the fixed collar are already known.
In addition, document U.S. Pat. No. 5,927,867 speaks of an attachment device consisting of a casing provided with projections, with said casing being coupled to the outer collar of the bearing with the projections fitting into a groove provided in the housing. In one mode of embodiment, the casing carries the sensor.
This mode of embodiment presents a number of disadvantages.
Specifically, it requires that a special casing be made for each type of sensor, or vice versa.
In addition, making the device in two separate pieces complicates assembly, which is undesirable, particularly in light of current production rates in the automobile industry.
Furthermore, it does not allow for the bearing to be attached securely enough inside the housing. In fact, the attachment is achieved merely by a housing seat that receives all of the stresses exerted by the bearing.
Finally, because the sensor is attached to the casing, which is capable of moving particularly in rotation under the effect of the stresses exerted on it, this mode of embodiment does not ensure precise positioning of the sensor in relation to the coder.
Also, particularly for safety applications such as anti-lock brakes or power steering, the sensor must be precisely and securely joined to the bearing in order for the sensitive components to always be opposite and at a distance from the coder.
The present invention provides a unit in which the sensor is made in monoblock construction with the bearing locking means inside the housing, with said means securely locking the bearing with the sensitive components of the sensor positioned precisely and securely opposite and at a distance from the coder.
To that end, and according to a first feature, the invention proposes a unit consisting of a bearing equipped with a data sensor device and a housing in which said bearing is coupled, in which:
said bearing consists of an inner turning collar designed to be attached to a turning body, an outer fixed collar coupled in the housing, and rolling bodies positioned between them;
said data sensor device consists of a coder that generates magnetic impulses attached to the turning collar and, attached to the fixed collar, a sensor equipped with at least two sensitive components capable of detecting such impulses;
said housing is designed to permit said bearing to be locked radially;
said housing has a first means to lock the bearing axially in one direction;
in which the sensor is made in monoblock construction with the second means to lock the bearing, with the second means being designed to work with the additional means provided in the housing to ensure that the bearing is locked in at least the other direction.
According to a second feature, the invention proposes an automobile steering system consisting of a steering column coupled to the inner collar of such a unit and a steering tube that receives said column in rotation, in which the housing is formed in the tube.
Other purposes and advantages of the invention will be revealed in the description that follows, made with reference to the attached drawings.